title: Temporal expression pattern of progesterone receptor in the uterine luminal epithelium suggests its requirement during early events of implantation.
abstract: OBJECTIVE
  To determine the precise timing of progesterone receptor (PR) disappearing from the uterine luminal epithelium (LE) to help understand the significance of the dynamic PR expression in the LE during embryo implantation.
  
  
  METHODS
  Experimental rodent models.
  
  
  METHODS
  University research laboratories.
  
  
  METHODS
  Mice and hamsters.
  
  
  METHODS
  Pseudopregnancy and artificial decidualization.
  
  
  METHODS
  Blue dye injection for detecting embryo attachment; immunohistochemistry, immunofluorescence, and in situ hybridization for detecting gene expression.
  
  
  RESULTS
  Progesterone receptor remained expressed in the LE up to 6 hours after the initial detection of blue dye reaction in mice (day 3, 22:00 hours), but disappeared first from LE cells at the implantation site and subsequently from the entire LE layer by day 4, 06:00 hours, when uterine stromal decidualization had become obvious. Progesterone receptor remained highly expressed in the LE of day 4 at 11:00 hours in pseudopregnant mice, but it disappeared from the entire LE layer by day 4 at 06:00 hours in artificially decidualized pseudopregnant mice.
  
  
  CONCLUSIONS
  Progesterone receptor disappears from the LE after implantation has initiated and before the histologic decidualization manifests, suggesting an active role of continued PR expression in the LE for the initial implantation process. The disappearance of PR expression in the LE is regulated by uterine factor(s) produced upon embryo attachment.
authors.affiliation: Department of Physiology and Pharmacology, College of Veterinary Medicine, University of Georgia, Athens, Georgia 30602, USA.
authors.forename: Honglu
authors.initials: H
authors.lastname: Diao
authors.forename: Bibhash C
authors.initials: BC
authors.lastname: Paria
authors.forename: Shuo
authors.initials: S
authors.lastname: Xiao
authors.forename: Xiaoqin
authors.initials: X
authors.lastname: Ye
mesh_terms: D000818:Animals; D006224:Cricetinae; D003656:Decidua / Q000378:metabolism; D010064:Embryo Implantation / Q000502:physiology; D004848:Epithelium / Q000378:metabolism*; D005260:Female; D008647:Mesocricetus; D051379:Mice; D008810:Mice, Inbred C57BL; D011247:Pregnancy; D011555:Pseudopregnancy / Q000378:metabolism; D011980:Receptors, Progesterone / Q000378:metabolism* / Q000502:physiology; D013997:Time Factors; D014599:Uterus / Q000378:metabolism*
chemical_list: D011980:Receptors, Progesterone